1. Astutik, Y. (2016). Communication Strategies Employed By Indonesian EFL Learners. In Communication Strategies Employed By Indonesian EFL Learners (pp. 29–41). Vietnam: Ton Duc Thang University. Retrieved from http://eprints.umsida.ac.id/252/
2. Bunga, S. (2017). Cognitive Strategies Used By The Second Graders of Junior High School In English Speaking Performance. Universitas Muhammadiyah Sidoarjo.
3. Corbin, J. M., & Strauss, A. L. (2015). Basics of qualitative research : techniques and procedures for developing grounded theory. San Jose, USA: Sage Publications.
4. Dansereau, D. F. (1985). Learning Strategy Research. Improving Thinking and Learning Skills: An Analysis of three approaches (Vol. 1). NewYork: Routledge.
5. Goh, C. C. M., & Burns, A. (2012). Teaching Speaking: A Holistic Approach. New York: Cambridge University Press.